1. Field of the Invention
The present invention relates to a semiconductor device and a method of fabricating the same. More particularly, the present invention relates to a fuse region of a semiconductor device and a method of fabricating the same.
2. Description of the Related Art
In general, semiconductor devices, i.e., chips, formed in a semiconductor substrate are electrically tested before an assembly process. Based on the test results, the semiconductor devices are classified as “bad” chips and “good” chips. When a malfunction of a bad chip occurs due to at least one failed cell, the failed cell is substituted with a redundant cell using a repair process. The repair process includes a step of laser beam illumination for blowing certain fuses so that the redundant cell may obtain an address of the failed cell in both read and write modes. When forming bit lines and word lines in a conventional semiconductor device, the fuses are formed on a same layer as the bit lines or word lines. However, as semiconductor devices become more highly integrated, each of the semiconductor devices has an increased height, which leads to a difficulty in forming a fuse window and blowing a fuse. Therefore, in order to facilitate these operations, a method of forming a metal fuse on a same layer as an upper metal wiring of the semiconductor device has been used.
FIG. 1 illustrates a cross-sectional view of a fuse region of a conventional semiconductor device.
Referring to FIG. 1, an interlayer insulating layer 100 is disposed on a semiconductor device (not shown). A fuse window 102 for blowing a fuse 104 is formed in the interlayer insulating layer 100. Fuses 104 are buried in the interlayer insulating layer 100 below the fuse window 102. During a repair process, any one of the fuses 104 may be blown by a laser beam penetrating the fuse window 102. However, when the fuses 104 are buried in the interlayer insulating layer 100, as described above, the repair process may not be reliable. More specifically, when any one of the fuses 104 is blown, the corresponding fuse may not be completely blown and a portion of the fuse 104 may remain in the interlayer insulating layer 100 as a residue. In particular, the residue is more likely to remain at a lower end of a sidewall B1 of the fuse 104. Further, when energy of the laser beam is increased to prevent such residues from remaining and to fully blow the fuse, fuses adjacent to the fuse to be blown may be damaged. The possibility that adjacent fuses may be damaged increases as a gap between the fuses 104 is reduced due to the increasing integration of semiconductor devices.
FIG. 2 illustrates a cross-sectional view of a fuse region of another conventional semiconductor device.
Referring to FIG. 2, a fuse window 202, in which fuses 204 are disposed, is disposed for blowing a fuse in an interlayer insulating layer 200. The fuses 204 are disposed such that some portions thereof may be buried in the interlayer insulating layer 200 below the fuse window 202. An insulating layer 206 conformably covers the fuses 204 and the interlayer insulating layer 200, and has a convex structure at each upper portion of the fuses 204. To blow a fuse in this conventional structure, a laser beam is focused on the fuse to be blown through the insulating layer 206. As a result, the fuse may be blown more easily. However, even in this case, the fuses 204 are partially buried in the interlayer insulating layer 200, so that the buried portions, especially, lower ends of sidewalls B2 in the interlayer insulating layer 200, may still lack reliability due to fuse residues.